4.2-5 V. Pan has discovered a way of multiplying 68 x 68 matrices using 132,464 mul tiplications, a way of multiplying 70 x 70 matrices using 143,640 multiplications, and a way of multiplying 72 72 matrices using 155,424 multiplications. Which method yields the best asymptotic running time when used in a divide-and-conquer matrix-multiplication algorithm? How does it compare to Strassen's algorithm